Frequency changing system



May 31, 1932. A. M. TROGNER FREQUENCY CHANGING SYSTEM Filed Oct. 8, 19262 Sheets-Sheet 1 INVENTOR.

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A TTORNEY May 31, 1932. M, TROGNER 1,861,371

FREQUENCY CHANGING SYSTEM Filed Oct. 8, 1926 2 Sheets-Sheet 2 :E IE- EP147"! Gin/[1911708 A AMMZ M; V

ATTORNEY Patented May 31, 1932 UNITED STATES PATENT OFFICE ARTHUR M. TROGNER, OF TAKOMA PARK, MARYLAND, ASSIGNOR, BY MESNE ASSIGN- MENTS, TOWIRED RADIO, 1110., OF NEW YORK, N. Y., A CORPORATION OF DELAWAREFREQUENCY CHANGING SYSTEM Application filed October 8, 1926. Serial No.140,376.

My invention relates broadly to high frequency signal transmissionsystems and more particularly to a switching system for effecting rapidchanges in the operating frequency of signal transmitters.

One of the objects of my invention is to provide a simplified system ofadjustment for a high frequency signal transmitter in which piezoelectric crystal devices are pref- 1o erably employed for controllingthe frequency of the transmitter.

Another object of my invention is to provide a frequency change systemfor transmission circuits in which a single control is provided foreffecting a change in the variables of the electrical circuits,simultaneously with the selection and connection of a piezo electriccrystal in the oscillator circuit.

A. further object of my invention is to provide a tuning system for acrystal controlled signal transmitter including a system of gearing bywhich the operation of a single control effects a selection of aparticular piezo electric crystal and adjusts the circuit variables ofthe transmitter corresponding to the frequency value of the crystal.

Other and further objects of my invention will. be understood from thefollowing specification by reference to the accompanying drawings inwhich v Figure 1 is a perspective view showing the schematic arrangementof the frequency changing system of my invention; Fig. 2 is a detailedfront elevational view showing the lost motion connection that may beprovided between the control shaft and the inductance system employed inthe tuning system of my invention; Fig. 3 is a diagrammatic circuit aarrangement of a radio transmitter employing, the frequency changingsystem of my invention; and Fig. 4 shows a schematic diagram of amodified form of frequency control apparatus embodying the principles of5 my invention.

In my Patent No. 1,609,744, granted December 7, 1926', on applicationSerial No. 113,791, filed June 4, 1926, for multiple piezo electriccrystal holder, I have described a sys tem of mounting a plurality ofpiezo electric crystal elements of different frequency characteristics.

My present invention is directed to a frequency changing systememploying apparatus such as is described in my aforementioned patent insuch manner that the operation of the several instrumentalities iscoordinated and a single control provided for effecting rapid changes infrequency in the electrical system in which the apparatus is connected'and selecting the desired piezo electric crystal while simultaneouslyeffecting the neces sary inductance changes in one or more parts of thecircuits for enabling the circuitsto be operated at a predeterminedfrequency.

My invention will be more clearly understood by a detailed reference tothe drawings wherein reference character 1 designates a frame structureprovided with extended arms 2 and 3 with supports 4 at one side thereofby which the rod members 5, 6 and 7 are sup ported in linessubstantially parallel to the axis of the inductance system. The rods ormetal strips provide supports for the memhere 8, 9, 10 and 11 which areprovided with contacting jaws 8a, 9a, 10a and 11a, respectively. A drum12 is mounted upon a shaft 15 journaled with respect to the framestructure 1, and on the strips 14 carried by the drum 12 there is woundthe conductive strip member 17 having its turns in spaced relation.Secured to selected points along the inductance 17, I provide contactmembers 20, 26, 50 and 51 arranged to engage the contacting jaws 10a,11a, 8a and 9a, respectively, as the drum is rotated.

A control wheel 36 is keyed to the shaft 15 and imparts rotary motion tomember 35 carried by the shaft 34. Shaft 34 is connected through bevelgear 33 with vertical shaft 32, which is in turn connected through bevelgears 31, for driving the rotary member 30. A second inductance systemdesignated generally at 27 is in this manner controlled simultaneouslywith the operation of the first inductance system by means of the rotarymember 29 on shaft 28 actuated by movement of rotary member 30. In orderto effect rotation of the inductance system I provide a hand wheelcontrolling a shaft periphery of the holder and arranged to beselectively connected in the control circuit inaccordance with changesin the values of the inductance in the inductance systems. In order topermit ready adjustment of the tuning system to the desired frequenciesthe larger wheels 35 and 30 of .the intermittent mechanism are providedwith tapped holes in their peripheries indicated at 43 in Fig. 2,

one for each piezo electric crystal in the multiple holder. Threadedpins 42 may be screwed into these holes at the points where switchmovement is desired. here various crystal frequencies are closetogether, it is desirable to effect the circuit tuning by means ofvariable condensers over bands of a number of crystals, it being onlynecessary to change the inductance values at the limits of these bands.

The pins 42 engage corresponding pins or projections on the smallerwheels 36 and 29 secured to the coil switch shafts. These pins orprojections correspond to the various switch positions as representedmore clearly in Fig. 2. Where it becomes necessary one coil switch maybe rotated at different times than the other coil switch by the properlocation of the pins, so that the system is highly practicable in itsoperation and arrangement.

In Fig. 3 I have shown a typical wiring diagram for a transmitterequipment with the frequency changing system of my invention. The movingelements have been shown at A, B and C, that is the piezo electriccrystal holder 46, inductance 17 and an inductance system 27. Theelectron tube 53 functions as the oscillator under control of theselected piezo electric crystal 44 or 45 in ac cordance with themovement of control handle 40. The inductance system shown at B iscontrolled through the wheels .35 and 36, while the inductance systemshown at C is controlled through wheels 29 and 30. The power amplifiertube 47 has its input circuit associated with the inductance 17 whileits output circuit is associated with the inductance 27 which isadjustably connected in the antenna ground circuit 4849.

It will be seen that where normally ten separate adjustments might berequired in a 60 radio transmitter, that is, one adjustment to shift thepiezo electric crystal control, three condenser adjustments and sixinductance tap adjustments, in the frequency changing sys tem of myinvention only four adjustments are required, one control being providedfor all of the inductance taps and for the selec tion of the properpiezo electric crystal and three adjustments for fixing the capacityvalues.

The practical problem solved by the frequency changing system is thesimultaneous control of all of the inductance taps as these are normallymore tedious and laborious to effect than the other adjustments. I havedesignated the conductive strips adjacent each of the inductances 17 and27 by reference characters 5, 6 and 7 and 5, 6 and 7 In Fig. 4, I haveillustrated schematically how the control apparatus may be modified foreliminating the large piezo electric crys tal holder 46 and replacingthe holder by a relatively few selected crystals which are connected inthe control circuit by properly arranged switch blades on the driveshaft. As an example, in this form, for positions 1 and 2 the circuitsmay be arranged so that the transmitter emits fundamental frequencies ofthe particular crystal selected. In positions 3 and 4 the output oramplifier circuit may be adjusted to emit the double frequency, and inpositions 5 and 6 the triple frequency, etc, while the crystal mastercircuit stays on the fundamental frequency.

WVhile I have described my invention as embodying piezo electric crystalelements as frequency determining elements, it will be understood thatother forms of frequency determining elements may be employed such assmall tuned circuits in place of the piezo electric crystal elements.The tuned circuits may be so arranged that a change in the connection ofa particular circuit may be effected simultaneously with the change ininductance in the transmission system.

l Vhile I have described my invention in its preferred forms, I desirethat it be understood that modifications may be made and that nolimitations upon the invention are intended other than are imposed bythe scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is as follows:

1. A frequency changing system for signal transmitting circuitscomprising in combination a variable circuit element arranged to beadjusted to a plurality of positions corresponding to differingfrequencies, a plurality of piezo electric crystal elements of differingfrequency characteristics, each mechanically shiftable to selectedpositions corresponding to the settings of said variable-circuit elementand means for simultaneously selecting a particular piezo electriccrystal element for particular positions of said variable circuitelement.

2. A frequency changing system for signal transmission circuitscomprising in combination a transmission circuit, a variable circuitelement arranged to be moved to a pluiii rality of selected positionsfor adjusting said transmission circuit to particular I differentfrequencies, and piezoelectric crystal apparatus having a plurality ofpiezoelectric crystal elements arranged to be mechanically shiftedsimultaneously with the change in position of said variable circuitelement and connections established between a selected piezo electriccrystal element and said transmission circuit for controlling thesignaling frequency of said transmission circuit.

c In a signal transmission system the combination of a transmittingcircuit, a variable circuit element connected in said circuit,'saidvariable circuit element having a plurality of differing positionscorresponding to different transmission frequencies, piezo electriccrystal apparatus containing a plurality of piezo electric crystalelements, each having a frequency corresponding to the plurality ofpositions to which said variable circuit element may be adjusted, andmeans for simultaneously rotatably adjusting said piezo electric crystalapparatusand said variable circuit element for the connection of aselected piezo electric crystal element in said signal transmittingcircuit.

4;. In a high frequency signal transmission system the combination of atransmitting circuit, a variable tuning element connected in saidcircuit and arranged to be adjusted to a plurality of selected positionscorresponding to different transmitting frequencies, piezo electriccrystal apparatus carrying a plurality of piezo electric crystalelements, each ground to different frequency characteristics, means formovably supporting said piezo electric crystal elements and means forsimultaneously moving said supporting means to selected positions andeffecting circuit connections between selected piezo electric crystalelements and selected portions of said variable tuning element forcontrolling the frequency of said transmitting circuit.

5. In a high frequency signal transmission system the combination of atransmitting circuit, avariable tuning element connected in said circuitand arranged to be adjusted to a plurality of selected positionscorresponding to different transmitting frequencies, a movably mountedpiezo electric crystal apparatus carrying a plurality of piezo electriccrystal elements, each ground to different frequency characteristics, anintermittent motion connection between said movabl mounted piezoelectriccrystal apparatus an said variable tuning element, and means forimparting movement to said movably mountedpiezo electric crys talapparatus for effecting intermittent motion of said variable tuningelement for selectively connecting one of said piezo elec tric crystalelements and a portion of said variable tuning element in saidtransmitting circuit for controlling the transmission frequency.

6., In a high frequency signal transmission system an electron tubeoscillator including input and output circuits, an inductance sys temconnected in said output circuit, a movable support carrying piezoelectric crystal apparatus thereon and including a pluralit of piezoelectric crystal elements having di ferent frequency characteristics,and means for connecting a selected portion of said inductance in saidoutput circuit simultaneously with the movement of said support for theconnection of a selected piezo electric crystal element in said inputcircuit for the control of said oscillator at a predetermined frequency.

7. In a high frequency signal transmission system the combination of anelectron tube having grid, filament and plate electrodes, circuitsinterconnecting said electrodes, a variable tuning element arranged tobe adjusted to a plurality of selected positions corresponding todifferent transmission frequencies, piezo electric crystal apparatusincluding a movable supporting frame, a plurality of piezo electriccrystal elements carried by said frame, each'having differing frequencycharacteristics, and means for simultaneously establishing connectionbetween said variable tuning element, said piezo electric crystalapparatus and said electrodes, for selected signaling frequencies.

8. In a high frequency signal transmission system the combination of aplurality of electron tubes each having grid, filament and plateelectrodes, input and output circuits interconnecting said electrodes, asignal transmission circuit, variable tuning elements interposed betweenthe output circuit of one of said electron tubes and said signaltransmission circuit and between the output circuit of another of saidelectron tubes and the input circuit of said aforementioned electrontube, piezo electric crystal apparatus including a movable carrierhaving a plurality of piezo electric [crystal elements positionedthereon each having different frequency characteristics, and means forsimultaneously moving said carrier and effecting adjustment of saidpiezo electric crystal apparatus and said variable tuning element.

9. A high frequency signal transmission system comprising an electrontube oscillator and power amplifier, assignal transmission circuit,variable inductance systems interposed between said signal transmissioncircuit and said power amplifier and between said oscillator and saidpower amplifier,

piezo electric crystal apparatus comprising a movable carrier having aplurality of piezo electric crystal elements of different frequencycharacteristics mounted thereon, and means for effecting simultaneousadjustments of said variable inductance systems with correspondingmovement of said movable carrier in selecting a particular piezoelectric crystal element for controlling the operating frequency of saidtransmission system.

10. In a high frequency signal transmission system the combination of arotatable inductance having a plurality of taps With cooperating contactmembers arranged adj acent thereto, piezo electric crystal apparatuscarrying a plurality of piezo electric crystal elements each havingdiffering frequency characteristics, a signal transmission circuit andcircuit connections by which a selected piezo electric crystal elementand a selected contact on said rotatable inductance may be included insaid circuit by the simultaneous rotation of said piezo electric crystalapparatus and said rotatable inductance.

11. In a high frequency signal transmission system a transmittingcircuit, a rotatable inductance arranged to be moved to a plurality ofpredetermined selected positions for establishing certain contacts, arotatable piezo electric crystal apparatus carrying a plurality of piezoelectric crystal elements thereon, and means for imparting rotarymovement to said rotatable piezo electric crystal apparatus forintermittently imparting movement to said rotatable inductance forcontrolling the transmission frequency of said transmitting circuit.

12. In a high frequency signal transmission system the combination of asignal transmitting circuit, a rotatable inductance arranged to be movedto a plurality of selected positions for the connection of selectedportions of said inductance in said signal transmitting circuit, arotatable piezo electric crystal carrier having a plurality of piezoelectric crystal elements of differing frequency characteristi csthereon, contacts for establishing connection with a selected piezoelectric crystal element and said transmitting circuit, and means forrotatably driving said piezo electric crystal apparatus and impartingintermittent rotation to said inductance for effecting simultaneousconnection of a portion of said inductance in said transmitting circuithaving a value proportioned to the frequency of a selected piezoelectric crystal element.

13. A frequency changing system for signal transmitting circuitscomprising in combination a variable circuit element arranged to beadjusted to a plurality of positions corresponding to differingfrequencies, a movable frame member, a plurality of piezo electricfrequency regulating elements of difiering frequency characteristicscarried by said movable frame member, and means for simultaneouslyshifting the position of said movable frame member and selecting aparticular frequency regulating element thereon for cooperation withcorresponding positions of said variable circuit element.

14. A frequency changing system for signal transmission circuits,comprising in combination, a transmission circuit, frequency regulatingapparatus including a movable carrier having a plurality of piezoelectric frequency regulating elements thereon, and a variable circuitelement arranged to be moved to a plurality of selected positions foradjusting said transmission circuit to corresponding frequencies,simultaneously with the change in position of said movable carrier forselectively setting said frequency regulating apparatus to a positionfor rendering effective a particular frequency regulating element of thedesired frequency.

15. In combination, a circuit responsive to electrical oscillations, avariable element in said circuit adapted to change the resonantfrequency thereof by changes in position of said element, a lurality ofpiezo electric frequency regulating elements and a movable supporttherefor, means for selectively connccting one of said frequencyregulating elements to said circuit by movement of said support, andmeans, co-acting with the first mentioned means, for moving saidvariable element to a position whereby said circuit is made resonant atsubstantially the frequency of said frequency regulating element.

16. A frequency changing device for a sig nal transmission systemcomprising a transmission circuit, a variable inductance elementarranged to be moved to a plurailty of selected positions for adjustingsaid transmission circuit to correspondingly different frequencies,piezo electric frequency control apparatus having a plurality of crystalelements arranged to be selectively connected into said transmissioncircuit, a unitary mechanical control for said inductance element andfor said piezo electric frequency control apparatus and rotatable meansto simultaneously effect crystal selection and movement of saidinductance element so as to maintain a frequency correspondencetherebetween.

17. A frequency changing device for a signal transmission systemcomprising a trans mission circuit, an inductance element the electricalcharacteristics of which are mechanically adjustable for tuning saidtransmission circuit to different frequencies, a

piezo electric frequency control apparatus having a plurality of crystalelements arranged to be selectively connected into said transmissioncircuit, a unitary mechanical control for adjusting said inductanceelement and for selecting one of the crystals in said T.

piezo electric frequency control apparatus, and rotatable means drivenby said unitary mechanical control for simultaneously effecting suitablecrystal selection and corresponding adjustment of said inductanceelement so as to maintain a frequency correspondence therebetween.

ARTHUR M. TROGNER

